In this continuing study of palate morphogenesis and effects of teratogens in causing cleft palate, the proposed research will be to determine whether the non-muscle (regions 2 and 3) and skeletal muscle (region 1) contractile system play a role in shelf movement. Morphological studies will be continued during the time that the palate shelves are rotating. The techniques of electron microscopy and immunofluorescence with anti-actin will be employed. The role of neurohormones in regulating the rotation of palate will be investigated in embryo cultures. Suitable antagonists will also be used to determine which neurohormone is involved in palate shelf rotation. A biochemical analysis of serotonin in the palate will be carried out. BIBLIOGRAPHIC REFERENCES: Wee, E., Wolfson, L. and Zimmerman, E. F. Palate Shelf Movement in Embryo Culture: Evidence for Skeletal and Smooth Muscle Contractility. Devel. Biol. 48:91-103 (1976). Zimmerman, E. F.: Palate Shelf Rotation in Embryo Culture. In: Tests of Teratogenicity In Vitro. Ebert, J. D. and Marois, M., Eds. North Holland, Amsterdam, pp. 449-464 (1976).